1. Field of the Invention
The present invention relates to a testing and annunciation device for verifying operation of the signalling system of a school bus and/or trailers. The testing device is contained within a small wheeled vehicle, and enables certain electrical and mechanical systems of the school bus to be monitored. The testing device containing vehicle is designed to be maneuvered, connected, and operated manually by one person.
2. Description of the Prior Art
School buses are equipped with many signalling and safety features. Illuminated signalling lamps of the school bus include: headlights, turn signal lights, four-way flashing lights, marker lights, tail lights, stop lights, beacon lights, reversing lights, and an eight-light warning system. Safety features may include redundant pneumatic braking systems and electrical braking systems of the type disclosed in the above-referenced parent patent. School buses must be inspected periodically for operability of these signalling and safety systems. The prior art will be discussed in the order of their perceived relevance to the present invention.
U.S. Pat. No. 4,617,510 issued on Oct. 14, 1986, to Axel Deicke et al. describes a testing installation for electric circuits of a motor vehicle comprising a generator which produces signals similar to the output signals of the control unit and feeds the same signals cyclically to the loads or the switches resulting only in the switching of the critical portions of the electric circuits to test their functional ability optically and acoustically. The present invention does not require a generator to test the electrical signal system of a school bus, and is not concerned with the testing of the driving motors for the windshield cleaner and heater fan.
U.S. Pat. No. 5,086,277 issued on Feb. 4, 1992, to Robert C. Hammerly describes an apparatus and method for performing diagnostic tests on the electrical systems of recreational vehicles and the like. The testing apparatus is coupled to a plug used to connect the electrical system of a towed or trailer vehicle with a main or powered vehicle. The testing involves the connection of each plug terminal to the tester apparatus and selectively activating to compare with expected values. The present invention is not concerned with the comparison of electrical signals with any expected values or the use of ammeters or volt meters.
U.S. Pat. No. 4,956,561 issued on Sep. 11, 1980, to Antanios B. Tamer describes a smart power connector for controlling the flow of electrical current from a vehicular smart power multiplexing network to the various peripheral devices and components of a vehicle. The instant invention does not require a complex multiplexing system.
U.S. Pat. No. 3,737,767 issued on Jun. 5, 1973, to Robert Slutsky describes a small diagnostic device which is directly plugged into a socket integral with a trailer. This device is usable only with vehicles having a seven conductor plug. The device cannot test marker lights independently of tail lights, as can the present invention, and, because it dedicates only one indicator to turn signals, cannot readily monitor a four-way flashing function.
U.S. Pat. No. 4,547,722 issued on Oct. 15, 1985, to Thomas J. Sarlo describes a diagnostic device mounted in a wheeled cart. This device is also limited to testing vehicles having the particular type of receptacle provided for.
U.S. Pat. No. 5,095,276 issued on Mar. 10, 1992, to James C. Nepil describes a circuit for diagnosing the operability of a trailer's electrical system. This circuit is considerably more complicated than that of the present invention, while not providing the versatility of present invention.
U.S. Pat. No. 4,866,390 issued on Sep. 12, 1989, to Joseph R. Butchko describes a vehicle light testing system for testing a plurality of lights using a scanning sequence which includes detection of shorts, bad grounds, and a low testing battery voltage. The present invention does not involve a scanning sequence and the testing of shorts, etc.
U.S. Pat. No. 4,884,032 issued on Nov. 28, 1989, to Kenneth R. LaPensee describes a tractor-trailer light system tester for military trailers having seven conductors, and includes the testing of light and brake switches. The present invention is not concerned with such testing, per se.
U.K. Patent Specification No. 1,477,700 published on Aug. 25, 1976, for Nissan Motor Company, Limited describes an apparatus for detecting faulty indicating lamps of a vehicle by connecting a common conductor with switch means and diodes to test the indicator lamps for the oil pressure, the voltage regulator and the generator. The present invention is not concerned with the operability of such indicator lamps.
German Patent Specification No. DE 2,724,670 A1 published on Dec. 12, 1978, describes a lighting system tester for trailers by using either a step-down transformer (220 V./12 V.) or the tractor's battery to test the stop lights, parking lights and turn signal lights with five separate switches. The present invention is capable of testing a greater number of lighting systems required by a school bus.
The prior art devices are particularly intended for use with trailers for over the road tractor and trailer combinations, and have electrical interface components specifically found on such combinations. The prior art devices lack the ability to be compatible with a variety of lighting systems present on a school bus.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.